1. Field of the Invention
The present invention relates to an automatic focusing device appropriate for use in a pick-up device, such as a video camera, a electronic still camera or the like.
2. Related Background Art
Conventionally, an image pick-up device such as a video camera is provided with a known method for focusing in which the focusing lens position is controlled by detecting the definition of an object image from the high-frequency component of a video signal which is output from pick-up means such as a CCD or the like, and making it maximum.
Further, in a camera converting an optical object image into an electric signal with such pick-up means, a method for the automatic focusing is proposed in which part of a picked-up picture is used as a focusing detection region, which is forced to follow the movement of the object to adjust into the focusing state automatically (e.g. Japanese Laid-Open Patent Application No. 60-249477.)
According to this conventional method, a move position of the object is obtained by sensing a characteristic point of the object within the focusing detection region and detecting the change thereof, and then the focusing detection region is reset on a small region centered on the move position.
However, since such a conventional pick-up device performs the tracking of an object with a focusing detection region of the same size and at the same response speed for every field in any of the pick-up situation, there occurs a problem that the focusing detection region may move unstably irrespectively of the object, for example, when the depth of field is large, in which it is difficult to distinguish a main object from the environment, i.e., background, in tracking the object to extract a peak of the high-frequency component of such object image (so-called a far and near contention).
It is a first objective of the present invention to resolve the above-mentioned problem by enabling the automatic object tracking adapted for a pick-up situation.
A second objective of the present invention is to provide an automatic object tracking device capable of tracking a moving object stably and reliably, whatever a pick-up situation may be.
A third objective of the present invention is to provide an automatic object tracking device capable of tracking a moving object precisely by controlling a moving range, response speed, moving direction, and size of the detection region, depending on the depth of field.
To accomplish these objectives, in accordance with a preferred embodiment of this invention, an image pick-up device capable of moving a detection region set on a picked-up picture by following the movement of an object image is disclosed, wherein the device comprises, position detection means for detecting an object position on said picked-up picture, region setting means for controlling a setting position of said detection region based on the output of said position detection means, and restriction means for restricting a moving range of said detection region according to a predetermined information of a pick-up state.
A fourth objective of the present invention is to provide an automatic focusing device capable of continuing to focus on a moving object, irrespective of the pick-up condition.
A fifth objective of the present invention is to provide an automatic focusing device capable of following an object image of interest, by making the movement of focusing detection region natural even when the depth of field is large.
To accomplish these objectives, in accordance with a preferred embodiment of this invention, an image pick-up device capable of moving a detection region set on a picked-up picture by following the movement of an object image is disclosed, wherein the device comprises position detection means for detecting an object position on said picked-up picture, region setting means for controlling a setting position of said detection region based on the output of said position detection means, and restriction means for restricting a moving range of said detection region according to an information of the depth of field.
A sixth objective of the present invention is to optimize the response characteristic to the tracking of an object, according to a pick-up condition.
To accomplish these objectives, in accordance with a preferred embodiment of this invention, an image pick-up device capable of moving a detection region set on a picked-up picture by following the movement of an object image is disclosed, wherein the device comprises position detection means for detecting an object position on said picked-up picture, region setting means for controlling a setting position of said detection region based on the output of said position detection means, and control means for controlling a response speed to the movement of said detection region according to an information of the depth of field.
A seventh objective of this invention is to provide a pick-up device capable of continuing to focus on a moving object, irrespective of the change of the depth of field.
To accomplish such an objective, in accordance with a preferred embodiment of this invention, an image pick-up device capable of moving a detection region set on a picked-up picture by following the movement of an object image is disclosed, wherein the device comprises position detection means for detecting an object position on said picked-up picture, region setting means for controlling a setting position of said detection region based on the output of said position detection means, and control means for controlling a moving direction, movement response speed, and size of said detection region according to an information of the depth of field.
An eighth objective of this invention is to provide an image pick-up device capable of performing a stable and reliable focusing operation for tracking an object, which permits the optimized control of a size, movement response speed, and moving direction of the focusing detection region at any time, irrespective of a pick-up condition, to enable the object to be positioned within the focusing detection region at all times.
A ninth objective of the present invention is to provide a pick-up device capable of continuing to focus on a moving object reliably, in which a main object is caught within a focusing detection region at any time, irrespective of the depth of field, with a stable and precise tracking of the object without malfunction such as a far and near contention, by switching and controlling appropriately the size, moving direction and response speed of the focusing detection region within a picked-up picture, depending on the depth of field.
A tenth object of the present invention is to provide a pick-up device with the automatic focusing adjustment having a mode of continuing to focus on a moving object while tracking the object, in which an operator can distinctly recognize a current mode of the focusing adjustment operation.
An eleventh object of the present invention is to provide a pick-up device capable of distinctly displaying on a monitor screen whether the current focusing detection mode is due to a fixed focusing detection region or a moving focusing detection region following the movement of an object, so that an operator can recognize a current focusing adjustment mode correctly, and various malfunctions and misoperations are prevented.
A twelfth objective of the present invention is to provide a focusing detection device capable of performing a stable and precise tracking of an object, by setting a first focusing detection mode in which the focusing operation is performed with the focusing detection region fixed at a predetermined position on a picked-up picture or a second focusing detection mode in which the focusing operation is performed with said detection region tracking the object, and in which said focusing detection region is displayed within a monitor screen, and further the current focusing detection mode, i.e., the on/off status of an automatic object tracking operation, is distinctly displayed within the monitor screen, as said first and second focusing detection modes have different displays for the focusing detection region, so that an operator can recognize a current pick-up condition correctly, and various malfunctions and misoperations can be prevented.
To accomplish these objectives, in accordance with a preferred embodiment of the present invention, an automatic focusing device is disclosed, in which the device comprises region setting means for setting a focusing detection region on a picked-up picture, object tracking means for controlling said region setting means by detecting the movement of an object image and moving a setting position of said focusing detection region by following said object image, focus control means for enabling the setting of a first focusing detection mode in which the focusing operation is performed with said focusing detection region fixed at a predetermined position on said picked-up picture, or a second focusing detection mode in which the focusing operation is performed with said detection region tracking the object, and display means for displaying said first focusing detection mode and said second focusing detection mode differently, as well as displaying said focusing detection region within a monitor screen.
A thirteenth objective of the present invention is to provide a pick-up device capable of distinctly displaying on a monitor screen such as an electronic view finder whether or not the current object tracking operation is performing a normal tracking of an object of interest, whereby an operator can recognize precisely the tracking operation condition in the current object tracking mode, and so various malfunctions and misoperations can be prevented.
Another objective of the present invention is to provide an automatic focusing device with the automatic object tracking feature enabling a stable and precise object tracking, which can continue to focus on a moving object by following the object, wherein the device can distinctly display on a monitor screen a state where the object tracking is normally performed to continue to focus on the moving object or a state where the object tracking is not normally performed so that the moving object is not focused on, because it is configured to display whether or not the object tracking operation is normally performed, with a decision from a condition of the focusing control system, whereby an operator can recognize precisely a current pick-up condition and various malfunctions and misoperations can be prevented.
To accomplish these objectives, in accordance with a preferred embodiment of the prevent invention, an automatic focusing device is disclosed, wherein the device comprises region setting means for setting a predetermined detection region on a picked-up picture, focusing detection means for detecting the focusing on an object image within said detection region, object tracking means for controlling said region setting means by detecting the movement of said object image and moving a setting position on said focusing detection region by following said object image, decision means for deciding an operation state of said object tracking means based on the output of said focusing detection means, and display means for displaying the operation state of said object tracking means based on a decision result from said decision means.
Other objectives and features of the present invention will become apparent from the following detailed description, in conjunction with the accompanying drawings.